These hop-derived bitter acids amp up beer’s ability to make the stomach secrete gastric acid. Iso-α-bitter acids (top right), which are produced during brewing, are among the most potent.

Credit: J. Ag. Food Chem.

Stomach Churning

These hop-derived bitter acids amp up beer’s ability to make the stomach secrete gastric acid. Iso-α-bitter acids (top right), which are produced during brewing, are among the most potent.

Credit: J. Ag. Food Chem.

On a hot summer day, sipping a cold brew can be a relaxing treat. But when the beer hits the stomach, it stimulates the release of gastric acid, an overabundance of which can lead to ulcers, acid reflux, and even stomach cancer. Now researchers report that the bitter acids derived from hops are key players in stimulating gastric acid secretion (J. Ag. Food Chem., DOI: 10.1021/jf204306z).

Previously, scientists had found that beer contains a cabal of compounds, such as ethanol, maleic acid, and succinic acid, that can promote gastric acid secretion. Veronika Somoza, of the University of Vienna, and her colleagues wanted to check out a class of compounds that hadn’t been studied yet: the bitter acids from hops.

So Somoza’s team tested five styles of German and Austrian brews: dark, wheat, lager, pilsner, and alcohol-free. They quantified each brew’s bitter compounds using high-performance liquid chromatography and then tested human gastric cells’ response to the beer and to its individual compounds. To detect gastric acid, the researchers monitored the cells’ proton secretion using a fluorescent dye. They also measured activation of four genes involved in gastric acid secretion through real-time quantitative polymerase chain reaction.

The team found that acid secretion began at concentrations of bitter acids, such as β-bitter acid, as low as 0.014 mg/L. In comparison, succinic acid promoted a similar level of gastric acid release at 35 mg/L. “The bitterest-tasting of the bitter acids stimulate gastric acid secretion more than less-bitter-tasting bitter acids,” Somoza says.

The findings are good news, she adds: Brewers could produce stomach-friendly beers by choosing their hops and controlling how long they heat the ingredients.

What about using this for good? Isn't it true that older people secrete less stomach acid and this affects their ability to absorb certain nutrients? A round of beer for the elderly might be a good thing.

Everything we eat stimulates the production of gastric acid via the proton pumps - the fact this MAY lead to acid reflux has little to do with the gastric acid production - this is a normal function of the digestive system. different foods and liquids cause different amounts of gastric acid production - this is natural - to suggest consumption of beer could lead to cancer is simply irresponsible science.
On the contrary, there are significant studies demonstrating the benefits of beer (hops) in calming the stomach.

Just to clarify this point--the researchers did not suggest beer alone causes cancer or those other health concerns. An oversecretion of gastric acid can lead to health impacts, certainly, but beer is just one very geographically widespread player, which is why the researchers looked at it in that context. And analyzing the activity of the bitter acids, which the researchers found to have quite a large gastric acid secretion impact for their concentration in the drink, could lead to brews that perhaps don't cause as much release of gastric acid.

Beer is a very complex drink, chemically, and can vary from brew to brew--and even batch to batch of the same brew. Getting a full idea of all the impacts it can have on humans will take a lot more research!

As an over 60 year old who is tired of indigestion after eating certain foods... I began to notice that when I consumed a nice bitter IPA... The indigestion never arrived! Then I started doing a little reasearch and found that hoppy IPA beers impart a bitter quality that stimulates gastric acid secretions. I also noticed that beers with alot of malt didn't give the same results. Even IPA's that list malt as a first ingredient. This is totally anecdotal however worth noting. And yes, I learned of antioxidant properties too... There is a healthy aspect to beer! Keep up the good work chemists!

Once have read that beer behaves pretty good in the digestive tract because it forms a bitter sugary foamy cover, a cover that protects and heals the lining of the stomach.

Another thing is that the hops in beer act as a female hormone (estradiol like component). An old publication mentioned that woman who take part in the harvest of hops synchronize their menses and that men tend to develop painful swollen pseudo breasts.